i have a bit of a problem sometimes when under power when u shift into the next gear the car dies and then picks back up
its had the usual mods done to it but its only runnin 175atws on 15 psi any ideas?

Yeah I sort of had the same problem. I had a stainless exhaust system 3'' put in and tuned. I work away so my car sits there for 2 weeks and I think possibly that I might of had a bad batch of fuel. I had it re-tuned and that has seemed to fix it. Try that.